Swivel chair



Sept. 21, 1965 G. HRACH 3,207,464

swIvEL CHAIR Filed April 25, 1964 IM BMM-1, Dowd-l wwln United States Patent O 3,207,464 SWIVEL CHAlR Gordon Hrach, Bedford, Ohio, assiguor to B. L. Marble Furniture, lne., Bedford, Ohio, a corporation of Ohio Filed Apr. 23, 1964, Ser. No. 362,055 Claims. (Cl. 248-417) This invention relates to chairs and, more particularly, to means for returning a swivel chair seat to a predetermined position.

Conventional swivel chairs, such as are provided at lunch counters, for example, have a base which is attached to the floor. A pedestal extends upright from the base and supports a seat for turning movement about the central axis of the pedestal. The chair, which usually has an upright back, may be turned to face away from the counter to facilitate getting into and out of the chair. A series of chairs are usually provided along the front of a counter and, since the chairs customarily are placed close together, it is necessary to turn the chair around to face in the direction away from the counter while getting into or out of the chair.

Where a row of chairs is provided along the front of a counter, it is desirable to provide some means for returning the chairs to a position facing toward the counter, when they are unoccupied. Otherwise, the empty chairs would be turned in a haphazard arrangement and they would give the counter a disorderly appearance.

Various devices have been suggested for urging swivel chairs toward a predetermined direction. In one form of self return swivel chair, for example, springs urge the chair toward a predetermined position when it is turned away from that position. The spring return type of swivel chair is objectionable because it urges the seat toward a front-facing position with a force which is proportional to the angular displacement of the seat. If the seat is given a relatively small angular displacement, the springs are ineffective and the seat may remain slightly turned from the desired position. The cam type swivel chair is also unsatisfactory because the occupant of the seat senses the vertical displacement of the seat as it rides up or down on the cam. This vertical movement causes the chair to appear to be unstable.

Another type of swivel chair includes a cam which urges the chair to return to a front facing position as soon as it is turned away from that position.

Many self-return swivel chairs are not capable of turning a ful-l 360. lf the angular displacement of the chair is limited, it is more difcult to get in and out of the seat. Furthermore, the design and the shape of the chair back and arms is restricted, since there must be sufficient space between the chairs for a person to slide into and out of the seat. 1f the chair is capable of turning a full 360, the arms and back of the chair do not hinder a person getting into and out of the seat.

A swivel type counter chair is subjected to severe wear and abuse and therefore it must be rugged in construction and capable of withstanding the wear over a long period of time. Since a large number of chairs usually are provided along the front of a counter, the swivel chair should be as inexpensive as possible. A slight cost saving in one self return chair therefore is multiplied many times in providing chairs for an entire counter. Heretofore, self return swivel chairs for counter seats have had relatively complicated and expensive self return devices.

In view of the defects .of the prior self return swivel chairs it is an object of this invention to provide an improved self return swivel chair.

It is a further object of this invention to provide in a chair a self return swivel mechanism having a minimum number of components.

3,207,464 Patented Sept. 21, 1965 'ice It is a still further object of this invention to provide a self return swivel chair which allows the seat to turn 360.

These objects are accomplished in accordance with the preferred embodiment of the invention by a pedestal tube which is fastened at its lower end to a base. A cam surface is formed on the upper end of the pedestal tube. A plurality of bushings are supported Within the central bore of the pedestal tube and a spindle is mounted in telescoping relation in the pedestal to and is journalled for rotation in the bushings. A chair seat is mounted on the upper end of the spindle and a roller is mounted on an axle extending radially outward from the spindle. The roller is supported on the cam surface for positioning the spindle longitudinally relative to the pedestal tube. The bushings in the pedestal tube form a low friction bearing which allows both rotational and longitudinal movement of the spindle relative to the tube. The lower p0rtion of the spindle has a wide radial groove formed therein and a set -screw extends through the pedestal tube and into the groove, but the end of the screw is spaced from the bottom of the groove. The groove is also substantially wider than the screw, which allows the spindle to rotate and to move axially relative to the pedestal tube as the roller rides over the cam. The set screw, however, engages the side of the groove to prevent the spindle from being pulled out of the pedestal.

The pedestal tube is oriented so that the low portion of the cam surfaces faces the counter and the slope of the cam surface is sufficient to cause the seat which is mounted on the spindle, to turn by its own weight to a position facing the counter. The roller has a low friction bearing and in combination with the bearing inserts in the pedestal tube, there is a minimum of frictional resistance to the turning of the seat.

This preferred embodiment of the invention is illustrated in the accompanying drawings in which:

FIG. l is a side elevational schematic view of the self return swivel chair of this invention;

FIG. 2 is an enlarged front elevational view of the chair pedestal assembly of this invention;

FIG. 3 is an enlarged side elevation view, partially in section, :of the chair pedestal assembly;

FIG. 4 is a cross sectional View of the pedstal assembly along the line 4-4 in FIG. 3; and

FIG. 5 is a schematic view of the cam surface profile.

Referring to FIG. l, a counter 2 is shown schematically. Typically, the counter 2 would be provided with a plurality of swivel chairs which are arranged at spaced intervals along the front of the counter, although only one chair 4 is shown in FIG. 1. Each of the counter chairs 4 includes a base 6 which is secured to the floor, an upright pedestal tube 8, and a spindle 10 which is telescoped in the tube 8. A seat 12 is mounted on the upper end of the spindle 10 and a back 14 is supported by the seat 12.

As shown in the enlarged views of FIGS. 2 and 3, the pedestal tube 8 has a central bore 16 of a relatively large diameter and a bore 18 of a smaller diameter, with a shoulder 20 between the bores 16 and 18. The ypedestal tube 8 is secured to the base 6 by a bolt, not shown, which extends through a threaded hole 22 and into a corresponding hole in the base 6. A plurality of cylindrical bushings 24 are inserted in the bore 16 in the tube 8 and the lowermost bushing 24 is supported on the shoulder 20. The bushings are preferably formed of bronze and have substantially the same dimensions.

The pedestal tube 8 has a cam surface 26 formed on the upper end thereof. The spindle 10 is telescoped in the tube 8 and an axle 28 is secured in the spindle 10fand extends radially outward from the spindle. As shown in FIGS. 2 and 3, a roller 30 is mounted for rotation on the 3 radial axle 28 and the roller 30 rests on the cam surface 26.

At its lower end, the spindle has a wide radial groove 32 formed therein. A screw 34 extends radially through the wall of the pedestal tube 8 and into the groove 32. The end of the screw 34, however, is spaced from the bottom of the .groove 32, so that the screw does not interfere with the rotation of the spindle. Axial movement -of the spindle 10 also is restricted except when the spindle 10 has been displaced to such an extent that the screw 34 engages the.A side wall of the groove 32. As the spindle 10 rotates,.the roller 30 rides on the cam 26 and the groove 32 is suciently wide to allow the spindle 10 to move axially upward as the roller rides over the high portion of the cam surfa-ce 26. The profile of the cam 26 is shown schematically in FIG. 5. As the spindle 10 turns through 360,the roller 30 lifts the spindle 10 upwardly relative to the pedestal tube 10.

. As shown in FIG. 1, the seat 12 is mounted on the spindle 10 with the front of the seat facing toward the counter 2 and with the roller 30 oriented at the lowermost portion of the cam surface 26. When the chair 4 is assembled as shown in FIG. 1, the seat 12 may be turned by the occupant Iaway from the counter 2 while getting into and out of the seat. As the seat 12 is turned relative to the pedestal 8, the roller 30` rides up on the sloping por-tion of the cam 26 and when the seat 12 is released, the force of gravity on the seat 12 urges the roller 30 toward the lowest portion of the cam 26. Accordingly, the seat 12 is returned to the position facing the center. Since the cam surface is substantially sinusoidal, as shown in FIG. 5, the maximum force urging the seat 12 toward a front facing position is applied when the seat is turned substantially 90 from the position facing the counter, where the slope of the cam surface 26 is a maximum. At the lowermost position of the roller 30 on the cam surface 26, the slope of the cam surface 26 is relatively small, thereby permitting a slight turning of the seat by the occupant with only a minimal restoring force urging the seat toward a position facing the counter.

Since the roller 30 rides freely on the cam surface 26, and the bushings -24 minimize the friction between the pedestal 8 and the spindle 10, the sl-ope of the cam and the total rise of the spindle on the cam 26 .are small. A benefit due to the low frictional resistance is that the cam surface has only a slight vertical rise and as the seat turns, the vertical displacement of the seat relative to the pedestal is almost imperceptible to a person sitting on the seat. The restoring force due to the weight of the seat on the cam is suicient, however, to return the seat to a position facing the counter when the seat is unoccupied. Accordingly, the seat is more comfortable to get into and out of and it is more stable. The swivel mechanism of this invention may be easily replaced or repaired simply by un- 'screwing the screw 34 and lifting the spindle 10 out of 4the tube 8. When the spindle 10 has been removed, the bushing 24 may .be inspected and replaced, if necessary. While this invention has been illustrated and described in one embodiment, it is recognized that variations and changes may be made therein without departing from the invention as set forth in the claims.

I claim:

1. A self return swivel chair comprising a base, an upright tube supported on the base, said tube having a continuous `axial cam surface formed integrally on the upper end thereof, a rotatable spindle telescoped in said tube, a cam follower, means mounting the cam follower on the spindle in position to engage the cam surface, a seat, and means for mounting the seat on the spindle.

2. A self return swivel chair comprising a base, an uprig-ht tube supported on the base, said tube having a cam surface on t-he upper end thereof, a rotatable spindle telescoped in said tube, an axle mounted on the rotatable spindle and extending radially outward from the spindle, a roller mounted for rotation on the axle and in position to enage the cam surface, a seat, and means for mounting the seat on the spindle.

3. A self return swivel chair comprising a base, an upright tube supported on the base, said tube having a cam surface on the upper end thereof, said tube having a relatively large diameter bore and a relatively small diameter bore in axial alignment, said large diameter bore extending from said cam surface to said small diameter bore, said bores having a shoulder therebetween, a bushing in the large diameter bore in engagement with the shoulder, a rotatable spindle telescoped in said tube, a cam f-ollower, means mounting the cam follower on the spindle in position to engage the cam surface, a seat, an-d means for mounting the seat on the spindle.

4. A self return swivel chair comprising a base, an upright tube supported on the base, said tube having a continuous axial cam surface on the upper end thereof, a rotatable spindle telescoped in said tube, said rotatable spindle having a radial groove therein, a screw extending through the tube and into the groove, said groove being substantially wider than the screw, a cam follower, means for mounting the cam follower on the spindle in position to engage the cam surface, a seat, and means for mounting the seat lon the Ispindle whereby the screw retains the spindle in the tube, but permits limited axial displacement of the spindle relative to the tube.

5. A self return swivel chair comprising a base, an upright tube supported on the base, said tube having a continuous axial cam surface on the upper end thereof, a rotatable spindle telescoped in said tube, a radial axle mounted on the spindle, a roller mounted for rotation on the laxle and in position to engage the cam surface, said spindle having a radial groove therein, a screw extending through the tube and into the groove, the width of the groove being greater than the displacement of the cam surface, a seat, and means for mounting the seat on the spindle. y

6. A self return swivel chair comprising a base, an upright tube supported on the base, said tube having a continuous, sinusoidal, axial cam formed integrally on the upper end thereof, said tube having a relatively large diameter bore aud a relatively small diameter bore in axial alignment, said large diameter bore extending from the cam surface to said small diameter bore, said bores having a lshoulder therebetween, a plurality of bushings` in the large diameter bore, said bushings being substantially equally dimensioned and the lower bushing being supported on the shoulder, a rotatable spindle telescoped in the tube and supported by the bushings for rotation, an axle mounted on the spindle and extending radially outward therefrom, a roller mounted for rotation on the axle Iand in position to engage the cam surface, said spindle having a radial groove therein, a screw extending through the tube and into the groove, said groove having a width greater than the displacement of the cam surface, a seat, and means for mounting the seat on the spindle.

7. In a swivel chair, a self return mechanism comprising .an upright tube, said tube having a continuous, sinusoidal, axial cam on the upper end thereof, said tube. having a relatively large da-meter bore and a relatively small diameter bore in axial alignment, said large diameter `bore extending from the cam surface to said small diameter bore, said bores having a shoulder therebetween, a plural-ity of bushings in the large diameter bore, said bushings being substantially equally dimensioned and the lower bushing being supported on the shoulder, a rotatable spindle telescoped in the tube and supported by the bushings for rotation, .an axle mounted on the spindle and extending radially' outward therefrom, a roller mounted for rota- Ition on the axle and in position to engage the cam surface, said spindle having a radial groove therein, and a screw extending through the tube and into the groove,` said groove having a width greater than the displacement of the cam surface. i

8. A chair swivel mechanism comprising a, urbe having a radial end surface, said tube having a sinusoidal cam formed integrally on said end surface, said cam project-ing :axially of said tube, ya rotatable spindle telescoped in said tube, a radial axle on said spindle, and a roller on said axle and in position to engage said cam, whereby the cam urges the follower towar-d a predetermined position.

9. A chair swivel mechanism comprising a tube having a radial end surface, said tube having a sinusoidal cam on said end surface and having large diameter and `small diameter bores in axial alignment, said cam projecting axially of said tube, said large diameter bore extending from said end surface to said small diameter bore, said bores having a shoulder therebetween, a bushing in the large dia-meter bore in engagement with the s-houlder, la rotatable spindle having one end telescoped in said tube, and means mounting ya follower on said spindle, said follower being spaced ya greater distance from said one end of said spindle than the length of said large diameter bore, whereby the spindle extends throughout the large diameter 'bore and is supported by said bushing.

10. A chair swivel mechanism comprising a tube having a radial end surface, said tube having a sinusoidal cam on said end surface, said cam projecting axially of said tube, a rotatable spindle telescoped in said tube, a radial Iaxle on said spindle, a roller on said axle and in position to engage said cam, said spindle having a radial groove ltherein, and a screw extending through the tube and into the groove, the width of t-he groove being greater than the displacement of -said cam, whereby the screw permits limited axial movement of the spindle.

References Cited by the Examiner UNITED STATES PATENTS 1,626,832 5/27 Huckel 248-418 1,695,725 12/28 Wolfe 248-417 1,897,676 2/33 Ries 24S-417 1,918,190 7/33 Miller et al 24S-417 2,351,194 6/44 Davies 248-417 2,518,429 8/50 Moorhead 74-56 3,107,891 10/63 Burke 248-417 CLAUDE A. LE ROY, Primary Examiner. 

1. A SELF RETURN SWIVEL CHAIR COMPRISING A BASE, AN UPRIGHT TUBE SUPPORTED ON THE BASE, SAID TUBE HAVING A CONTINUOUS AXIAL CAM SURFACE FORMED INTEGRALLY ON THE UPPER END THEREOF, A ROTATABLE SPINDLE TELESCOPED IN SAID TUBE, A CAM FOLLOWER, MEANS MOUNTING THE CAM FOLLOWER ON THE SPINDLE IN POSITION TO ENGAGE THE CAM SURFACE, A SEAT, AND MEANS FOR MOUNTING THE SEAT ON THE SPINDLE. 